if u have a stock yfz n are cheap (like me) n want some HP heres the steps

1) take off air box lid
2)take out baffle
3) take off pipe
4) take somethng that can cut n cut at the end and beging of the pipe (muffler)
5)take all packin out
6)weld the pipe back together
7)rejet if u can!

bout 8hp right there........n a sleeper!!!

 

Yeah but now your talking Loud pipes and most of us wouldn't be able to get into the ride parks or dunes !!!!!

 

baffle back in -2 hp

and its way less noise than my gytr when it had baffle out

 

If you don't do number 7, your in for alot of work fixing a blown engine.

 

i dont think you gain 8 HP... maybe 3-5 max from that stuff.

 

please elaborate on the blown engine concept if you dont rejet ?!?!?!?!

 

It will be lean and, lean is BAD!

Lean engines will seize up and, that will = Blown!

 

couldnt you adjust the carbs to compensate for this?! also would changing the jets void a warranty on a new bike?

 

no it doesnt void it.

 

Check my "GYT-R pipe smoked yfz engine" thread. Engine didn't sieze, but it smokes like a 2-stroke now. GYT-R pipes are crap.